Stereophonic loudspeaker system and method of use thereof

Abstract

An improved loudspeaker system that produces an improved audio quality for stereophonic sound, which can be described as 3D audio. In one embodiment, the improved loudspeaker utilizes at least three stacks of electrostatic transducer cards, with one of the stacks located between the other two stacks. While there is generally some crossover between the frequencies of the stacks of electrostatic transducers, the middle stack will be directed to the lower frequency ranges and the other two stacks will be directed to the higher frequency ranges. Each of the three card stacks will utilize multi-track audio recordings, such as two-track audio recordings, which are modified for each of the three card stacks. In an alternative embodiment, the improved loudspeaker can utilize a conventional voice-coil driver in lieu of the middle stack of electrostatic transducer cards.

Claims

1. A loudspeaker system comprising: (a) a middle speaker operable for emitting audible sound in a first range between 20 Hz and an upper set point frequency; (b) a first end speaker comprising a plurality of a first stack of cards having electrostatic transducers, wherein (i) the first end speaker is attached at or near a first end of the middle speaker, and (ii) the first end speaker is operable for emitting audible sound in a second range between a lower set point frequency and 20 kHz; and (c) a second end speaker comprising a plurality of a second stack of cards having electrostatic transducers, wherein (i) the second end speaker is attached at or near a second end of the middle speaker such that the middle speaker is between the first speaker and the second speaker, (ii) the second end speaker is operable for emitting audible sound in the second range between the lower set point frequency and 20 kHz, and (iii) the loudspeaker system is operable to emit sound based upon an audio track recording comprising a first track (T.sub.1) and a second track (T.sub.2), wherein (A) the middle speaker is operable to emit sound based upon a weighted average of the first track (T.sub.1) and the second track (T.sub.2), (B) the first end speaker is operable to emit sound based upon the first track (T.sub.1) modified by at least some subtraction of the second track (T.sub.2) utilizing a second formula (1+x)T.sub.1−(y)T.sub.2, (C) the second end speaker is operable to emit sound based upon the second track (T.sub.2) modified by at least some subtraction of the first track (T.sub.1) utilizing a third formula (1+x)T.sub.2−(y)T.sub.1, and (D) each of x and y is in a range between 0 and 1.5 for the second formula and the third formula.

2. The loudspeaker system of claim 1, wherein (a) the upper set point frequency is at most 1000 Hz; and (b) the lower set point frequency is at least 200 Hz.

3. The loudspeaker system of claim 1, wherein the first stack of cards has a stack card width that is the same as the second stack of cards.

4. The loudspeaker system of claim 1, wherein the middle speaker comprises a plurality of a third stack of cards having electrostatic transducers.

5. The loudspeaker system of claim 1 further comprising: (a) a first transformer to power the first stack of cards in the first end speaker; and (b) a second transformer to power the second stack of cards in the second end speaker.

6. The loudspeaker system of claim 5 further comprising a motherboard having a voltage inverter, wherein (a) the voltage inverter has a first channel through which power can be routed through the first transformer to power the first stack of cards; and (b) the voltage inverter has a second channel through which power can be routed through the second transformer to power the second stack of cards.

7. The loudspeaker system of claim 1, wherein the loudspeaker system has a changeover set point frequency.

8. The loudspeaker system of claim 7, wherein (a) the upper set point frequency is greater than the changeover set point frequency; and (b) the lower set point frequency is less than the changeover set point frequency.

9. The loudspeaker system of claim 8, wherein (a) the middle speaker is operable for emitting audible sound at a decreasing volume percentage between the changeover set point frequency and the upper set point frequency, in which, at the changeover set point frequency, the volume percentage is 100% and, at the upper set point frequency, the volume percentage is 0%; and (b) the first end speaker and the second end speaker are each operable for emitting audible sound at an increasing volume percentage between the lower set point frequency and the changeover set point frequency, in which, at the lower set point frequency, the volume percentage is 0% and, at the changeover set point frequency, the volume percentage is 100%.

10. The loudspeaker speaker of claim 1, wherein the loudspeaker system is operable to vary x and y independently.

11. The loudspeaker system of claim 1 further comprising a controller that is operable to vary x and y independently.

12. The loudspeaker speaker of claim 1, wherein x and y are dependent upon one another.

13. The loudspeaker system of claim 12 further comprising a controller that is operable to vary x.

14. The loudspeaker system of claim 13, wherein the controller is a hand held controller.

15. The loudspeaker system of claim 1, wherein the loudspeaker system has a null sound plane.

16. A method comprising: (a) selecting an audio track recording comprising a first track (T.sub.1) and a second track (T.sub.2); and (b) utilizing a loudspeaker system to emit audible sound based upon the audio track recording, wherein (i) a middle speaker of the loudspeaker system is utilized to emit audible sound (I) in a first range between 20 Hz and an upper set point frequency and (II) based upon a weighted average of the first track (T.sub.1) and the second track (T.sub.2), (ii) a first end speaker of the loudspeaker system is utilized to emit audible sound (I) in a second range between a lower set point frequency and 20 kHz, and (II) based upon the first track (T.sub.1) modified by at least some subtraction of the second track (T.sub.2) utilizing a second formula (1+x)T.sub.1−(y)T.sub.2, wherein (A) the first end speaker comprises a plurality of a first stack of cards having electrostatic transducers, and (B) the first end speaker is attached at or near a first end of the middle speaker; and (iii) a second end speaker of the loudspeaker system is utilized to emit audible sound (I) in the second range between the lower set point frequency and 20 kHz, and (II) based upon the second track (T.sub.2) modified by at least some subtraction of the first track (T.sub.1) utilizing a third formula (1+x)T.sub.2−(y)T.sub.1, wherein (A) the second end speaker comprises a plurality of a second stack of cards having electrostatic transducers, (B) the second end speaker is attached at or near a second end of the middle speaker such that the middle speaker is between the first speaker and the second speaker, and (C) each of x and y is in a range between 0 and 1.5 for the second formula and the third formula.

17. The method of claim 16, wherein (a) the upper set point frequency is at most 1000 Hz; and (b) the lower set point frequency is at least 200 Hz.

18. The method of claim 16 further comprising: (a) utilizing a first transformer to power the first stack of cards in the first end speaker; and (b) utilizing a second transformer to power the second stack of cards in the second end speaker.

19. The method of claim 18, wherein (a) the loudspeaker system further comprises a motherboard having a voltage inverter, and (b) the method further comprises (i) utilizing a first channel of the voltage inverter to route power through the first transformer to the first stack of cards, and (ii) utilizing a second channel of the voltage inverter to route power through the second transformer to the second stack of cards.

20. The method of claim 16, wherein the loudspeaker system has a changeover set point frequency.

21. The method of claim 20, wherein (a) the upper set point frequency is greater than the changeover set point frequency; and (b) the lower set point frequency is less than the changeover set point frequency.

22. The method of claim 21, wherein (a) the middle speaker is utilized to emit audible sound at a decreasing volume percentage between the changeover set point frequency and the upper set point frequency, in which, at the changeover set point frequency, the volume percentage is 100% and, at the upper set point frequency, the volume percentage is 0%; and (b) each of the first end speaker and the second end speaker are utilized to emit audible sound at an increasing volume percentage between the lower set point frequency and the changeover set point frequency, in which, at the lower set point frequency, the volume percentage is 0% and, at the changeover set point frequency, the volume percentage is 100%.

23. The method of claim 16, wherein each of x and y is in a range between 0.25 and 1.25 for the second formula and the third formula.

24. The method of claim 16, wherein the method further comprises varying x and y independently.

25. The method of claim 16 further comprising utilizing a controller to vary x and y independently.

26. The method of claim 16, wherein x and y are dependent upon one another.

27. The method of claim 26 further comprising utilizing a controller to vary x.

28. The loudspeaker system of claim 11, wherein the controller is a hand held controller.

29. The loudspeaker system of claim 1, wherein each of x and y is in a range between 0.25 and 1.25 for the second formula and the third formula.

Description

DESCRIPTION OF DRAWINGS

(1) FIGS. 1A-1E (which are reproduced from the Pinkerton '353 patent) depict an electrically conductive membrane pump/transducer that utilizes an array of electrically conductive membrane pumps that cause a membrane to move in phase. FIGS. 1A-1B depict cross-section views of the pump/transducer. FIGS. 1C-1E depict overhead views of the pump/transducer.

(2) FIG. 2 (which is reproduced from the Pinkerton '353 patent) depicts an electrically conductive membrane pump/transducer that has a stacked array of electrically conductive membrane pumps.

(3) FIG. 3 (which is reproduced from the Pinkerton '353 patent) depicts an electrically conductive membrane pump/transducer that utilizes an array of electrically conductive membrane pumps that operates without a membrane or piston.

(4) FIG. 4 (which is reproduced from the Pinkerton '353 patent) depicts an electrically conductive membrane pump/transducer 3100 that utilizes an array of electrically conductive membrane pumps and that also includes an electrostatic speaker.

(5) FIG. 5 (which is reproduced from the Pinkerton '353 patent) depicts an electrically conductive membrane pump/transducer 3200 that utilizes an array of electrically conductive membrane pumps that cause a membrane to move in phase and that also includes an electrostatic speaker.

(6) FIG. 6A (which is reproduced from the Pinkerton '313 patent) illustrates an electroacoustic transducer (“ET,” which is also referred to as a “pump card”) and its solid stator.

(7) FIG. 6B (which is reproduced from the Pinkerton '313 patent) is a magnified view of the electroacoustic transducer of FIG. 6A.

(8) FIG. 6C (which is reproduced from the Pinkerton '313 patent) illustrates the electroacoustic transducer of FIG. 6A having a single stator card before trimming off the vent fingers.

(9) FIG. 7 (which is reproduced from the Pinkerton '313 patent) is exploded view of the electroacoustic transducer of FIG. 6A.

(10) FIG. 8A (which is reproduced from the Badger '088 PCT application) illustrates an exploded view of an electroacoustic transducer.

(11) FIG. 8B (which is reproduced from the Badger '088 PCT application) illustrates the electroacoustic transducer shown in FIG. 8A in fabricated form.

(12) FIGS. 9A-9B (which are reproduced from the Pinkerton '073 application) illustrate a loudspeaker with stacked arrays of electrostatic venturi membrane-based pump/transducer (EVMP) cards.

(13) FIG. 10 (which is reproduced from the Pinkerton '438 PCT application) illustrates a dipole loudspeaker having electrostatic transducers.

(14) FIGS. 11A-11B (which are reproduced from the Pinkerton '438 PCT application) illustrate the null sound plane (NSP) of the speaker of FIG. 10.

(15) FIG. 12A is an illustration of an embodiment of the present invention.

(16) FIG. 12B is a photograph of three card stacks that are similar to the card stacks illustrated in FIG. 12A (including widths and orientation).

(17) FIG. 13 is an illustration of a controller that includes the ability to control independently the increase of intensity of one channel and some elimination (subtraction) of the other channel of two audio-track recordings.

(18) FIG. 14 is an illustration of a controller that includes the ability to control together the increase of intensity of one channel and some elimination (subtraction) of the other channel of two audio-track recordings.

DETAILED DESCRIPTION

(19) The Pinkerton Patents and Applications disclose and teach loudspeakers in which the loudspeaker has a plurality of stacks of cards having electrostatic transducers, in which one stack of cards has a different width as another stack of cards in the plurality of stacks. At frequencies above a 200 Hz, and at the same drive voltage and current, the stack of lesser width produced significantly greater microphone voltage as compared to the stack of greater width cards. By combining the plurality of stacks of cards with different widths, this provides for the elimination of conventional cone drivers, and provides for improved sound both above and below 200 Hz using only electrostatic transducers. It also assists in maintaining a null sound plane that is beneficial for voice recognition.

(20) As shown in FIG. 12A, loudspeaker system 1200 includes at least three card stacks 1201-1203. Card stack 1201 is the middle between card stack 1202 and card stack 1203. Card stack 1201 (which optionally can be a plurality of card stacks) contains the wider cards, as compared to the card stacks 1202 and 1203 (each of which optionally can be a plurality of card stacks). The “card width” is the span of the membrane of a card in the card stack. For example, the card width of card stack 1201 can be 21 mm (which 21 mm card width is the span of the membrane of the cards in card stack 1201), such as described and taught in the Pinkerton '669 application and the card width of each of the card stacks 1202-1203 can be 12 mm (which, 12 mm card width is the span of the membrane of the cards in card stacks 1202-1203). Generally, the card width of each of the card stacks 1202-1203 is the same.

(21) As shown in FIG. 12A, each of the card stacks 1202-1203 has been rotated 90°, as compared to card stack 1201. I.e., per the orientation of FIG. 12A, the cards in the card stack 1201 run horizontally (and such cards are stacked vertically), while the cards in each of the card stacks 1202-1203 run vertically (and such cards are stacked horizontally). FIG. 12B is a photograph of a wider card stack 1211 and two narrower card stacks 1212-1213 that are similar to the stacks described above (including widths and orientation) for card stacks 1201-1203, respectively, of loudspeaker system 1200.

(22) In other embodiments the cards in each of the card stacks 1201-1203 can be in the same plane. For example, all of the card stacks can be horizontal, with narrower width card stacks on the top and bottom of a middle wider width card stack. Loudspeaker system 1200 has two transformers 1204-1205, which power card stacks 1202-1203, respectively. A high voltage inverter (on motherboard 1207) powers the card stack 1201, with one channel of an off-the-shelf inverter routed through transformer 1204 to power card stack 1202 and a second channel of the same off-the-shelf inverter routed through the transformer 1205 to power card stack 1203.

(23) Additionally, loudspeaker system 1200 has control buttons 1206 and speaker feet 1208.

(24) For definitional purposes, the two-audio track recordings will be referred to herein as having a “first track” (abbreviated “T.sub.1”) and a “second track (abbreviated “T.sub.2”).

(25) Moreover, the frequency ranges of (a) card stack 1201 and (b) card stacks 1202-1203 will be different. Card stack 1201 is directed to lower frequency ranges (such as a changeover set point of 300 Hz and below). Card stacks 1202-1203 will each be directed to higher frequency ranges (such as a changeover set point of 300 Hz and above). Even though the changeover set points can be the same (such as at 300 Hz), card stacks 1201-1203 will have some crossover. For example, for card stack 1201, it will have an upper set point (such as 1000 Hz) in which card stack 1201 emits 0% sound above this upper set point and 100% sound at the changeover set point (such as the 300 Hz changeover set point), with a transition (such as a linear transition between the upper set point and the changeover set point). Similarly, for example, for card stacks 1202-1203, each will have a lower set point (such as 200 Hz) in which card stack emits 0% sound below this lower set point and 100% at the changeover set point (such as the 300 Hz changeover set point), with a transition (such as a linear transition between the lower set point and the changeover set point). Controls for such crossovers are known in the art.

(26) With respect to the first track and the second track of the two-audio track recordings, each of the card stacks 1201-1203 emits sound (in their respective frequency ranges) based upon a combination of these two tracks.

(27) For card stack 1201, the first and second tracks generally are averaged. The formula for this is:
(T.sub.1+T.sub.2)/2  (1)

(28) In alternative embodiments, the first and second tracks can be a weighted average, which optionally can be controlled.

(29) For card stack 1202, the modified track for card stack 1202 will be the first track (typically with some increase in intensity) additionally modified by some elimination (subtraction) of the second track. A formula for this is:
(1+x)T.sub.1−(y)T.sub.2  (2)

(30) For card stack 1203, the modified track for card stack 1203 will be the second track (typically with some increase in intensity) additionally modified by some elimination (subtraction) of the first track. A formula for this is:
(1+x)T.sub.2−(y)T.sub.1  (3)

(31) For both equations (2) and (3), the values of x and y can be, respectively, 0≤x≤1.5 and 0≤y≤1.5. Typically, the values of x and y in this range (such as between 0 and 1.5, inclusive) are approximately the same, which has the effect of normalizing loudness of the resulting modified tracks for each of card stacks 1202-1203. In some embodiments, the values of x and y are both at 0.75. In some embodiments, each of x and y is in the range between 0.25 and 1.25, and, in further embodiments, each of x and y is in the range between of 0.5 and 1.

(32) Since x and y can be varied independently of one another (such as between 0 and 1.5, inclusive), a controller, such as controller 1300 shown in FIG. 13, can be used to control independently x and y in equations (2) and (3). As shown in FIG. 13, in addition to controls for bass 1301 and treble 1302, the controller has controls for x (“3D.sub.x”) 1303 and for y (“3D.sub.y”) 1304. The midpoint of controls 1303-1304 can be set at some pre-determined amounts, such as 0.75 for both x and y.

(33) In alternative embodiments, x and y can be dependent upon one another, such as x being equal to y (which again will generally normalize loudness for the modified tracks). In such event equations (2) and (3) will be, respectively, equations (2)* and (3)*.
T.sub.1+x(T.sub.1−T.sub.2)  (2)*
T.sub.2+x(T.sub.2−T.sub.1)  (3)*

(34) Again, x can be between 0 and 1.5, inclusive. In some embodiments, x is in the range between 0.25 and 1.25, and, in further embodiments, x is in the range between of 0.5 and 1.

(35) For these embodiments, a controller, such as controller 1400 shown in FIG. 14, can be used to control x in equations (2)* and (3)*. As shown in FIG. 14, in addition to controls for bass 1401 and treble 1402, the controller has controls for x (“3D”) 1403. The midpoint of controls 1403 can be set at some pre-determined amount, such as 0.75 for x.

(36) The loudspeaker systems of the present invention produced an audio quality that was surprisingly advanced over prior art loudspeaker systems. Such configurations achieved further stereo separation and an increase in audio quality, which can be described as 3D audio. The sound emitted was as if instruments and voices were spread out around the room even though the speakers in the speaker system were all in the same device (which was small and portable). Without being bound by theory, it is believe that this effect is due to the unique combination of utilizing electrostatic card stacks (which tend to beam sound like a flashlight beams light) and the use of the modified first and second tracks in each of the various card stacks. Regardless of the theory, the resulting sound from the loudspeaker systems of the present invention is quite striking.

(37) For the tweeter card stack on the first side (i.e., card stack 1202), it appears that subtracting the second channel signal from the first tweeter stack helps to cancel some of the second channel signal from the first near portion of the middle card stack driver (i.e., card stack 1201). (The “first nearer portion of the middle card stack driver” is the side of the middle card stack driver that is adjacent to the first tweeter stack; conversely, the “second nearer portion of the middle card stack driver” is the side of the middle card stack driver that is adjacent to the second tweeter stack”). This arrangement makes the first near portion of the middle card stack driver appear to produce more first channel signal than second channel signal. This, in part, is due to the crossover of frequencies of the middle card stack driver and the first tweeter stack.

(38) For the tweeter card stack on the second side (i.e., card stack 1203), it appears that a similar process causes the second near portion of the middle card stack driver (i.e., card stack 1201) to produce more of the second channel signal. Again, this makes the second near portion of the middle card stack driver more like the second card stack than simply a mono middle card stack driver.

(39) It is further believed that another characteristic of the electrostatic drivers that is likely helping to produce the 3D effect (and enhanced stereo separation) is that the motion of electrostatic membranes is in phase (generally always in phase) with the audio signal. Traditional electrodynamic cone drivers are known to often be out of phase with the audio signal due to electrical and mechanical resonances (and also due to the relatively high inertia of the moving copper coil). The fact that the small and larger drivers of the present invention are in phase (generally always) with the audio signal likely enhances the stereo separation and 3D effect. In other words, cone drivers produce audio waves that do not always add or subtract completely due to their phase differences, whereas electrostatic driver audio signals add/subtract completely and are thus better able to produce enhanced stereo/3D effects.

(40) In an alternative embodiment, the middle card stack (card stack 1201) of loudspeaker system 1200 can be replaced with a conventional driver, and then utilized in a similar manner as discussed above. While the presence of the middle card stack 1201 enhances the 3D effects, the 3D effects still appears (primarily, but not to the same degree) due to the use of the two card stacks 1202-1203 with the convention driver (that is usually used for the bass frequencies). Testing has revealed that in this alternative embodiment, there remained some beneficial interaction between the conventional bass driver and the tweeter card stacks that accentuates both stereo separation and the 3D effect.

(41) While embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. The scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

(42) The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated herein by reference in their entirety, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.

(43) Amounts and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly recited limits of 1 to approximately 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than approximately 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

(44) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.

(45) Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

(46) Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

(47) As used herein, the term “about” and “substantially” when referring to a value or to an amount of mass, weight, time, volume, concentration or percentage is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed method.

(48) As used herein, the term “substantially perpendicular” and “substantially parallel” is meant to encompass variations of in some embodiments within ±10° of the perpendicular and parallel directions, respectively, in some embodiments within ±5° of the perpendicular and parallel directions, respectively, in some embodiments within ±1° of the perpendicular and parallel directions, respectively, and in some embodiments within ±0.5° of the perpendicular and parallel directions, respectively.

(49) As used herein, the term “and/or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and/or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D.